The argument for head angle sounds good, but in practice it doesn't matter. An awful darn lot of houses were framed with hammers that have the head perpendicular to the handle. If it were essential, they'd have started making hammers with angled heads sometime in the last 3,000 years.
Source: am a furniture maker, professionally. I've switched from using a joiner's mallet to a lump hammer, so I have experience with both. The lump hammer faces are perpendicular to the handle, not angled in the slightest. Better ones have slightly domed faces, so if you're walloping a piece together and don't have time to grab a block to protect it (time moves faster once the glue is on), you're less likely to leave a bruise from the edge of the face if you don't hit it with the face of the hammer/mallet dead square to the wood.
In practice, you also aren't usually swinging in an arc when you hit a nail or chisel either. You start your swing in an arc, and transition to a flatter trajectory as you approach the end of the swing so you have less motion in the plane of the face of the head as you're hitting the nail/chisel. Or in other words, you want the head traveling along the axis you're trying to drive the nail/chisel so you don't skew it off axis.
I've always gotten so little done in wood working because I love making tools more than furniture. This was great. It's a good example of how unintuitive but important knowledge is everywhere in tool-use and design, too. I'd never seen this approach to creating mallet head angles, and when I've done it in the past, I literally eyeballed it. Whoops. Maybe that's why I don't use the mallet so often.
My favorite part of these woodworking diaries is when they inevitably make a minor mistake like hammer in the wedge too early, or fasten/glue something upside-down. It's a delightful little window into their thought process, and the sort of complacency we see in other crafting disciplines.
I’m impressed a 2010 web page is still up. The links at the end are pretty much all dead. I have actually wondered what the angle should be when I turn a mallet—now I know.
I like marking the date with the stamp of a penny. I knew a builder who did similar on a home and used pennies as washers in a few places— date visible of course.
Otherwise good write up and never used a hammer or mallet with angled face
Source: am a furniture maker, professionally. I've switched from using a joiner's mallet to a lump hammer, so I have experience with both. The lump hammer faces are perpendicular to the handle, not angled in the slightest. Better ones have slightly domed faces, so if you're walloping a piece together and don't have time to grab a block to protect it (time moves faster once the glue is on), you're less likely to leave a bruise from the edge of the face if you don't hit it with the face of the hammer/mallet dead square to the wood.
In practice, you also aren't usually swinging in an arc when you hit a nail or chisel either. You start your swing in an arc, and transition to a flatter trajectory as you approach the end of the swing so you have less motion in the plane of the face of the head as you're hitting the nail/chisel. Or in other words, you want the head traveling along the axis you're trying to drive the nail/chisel so you don't skew it off axis.
Familiar impulse among software engineers.